A V-shaped hybrid mass damper has been developed with a view to reducing the vibration induced by wind or earthquake excitation on a 230m high-rise building. The passive pendulum mechanism comprised of a Vshaped sliding mass is combined with the active control of the mass movement driven by a servo motor, and the mechanical system has been further refined for compactness and easy operation of tuning the natural frequency. The high performance of the device has been verified by numerical analyses and experimental tests conducted in a laboratory prior to its installation in the building concerned.
To minimize the necessity to suspend shackling work floating crane on account of vessel rolling, an active mass damper system was developed to attenuate oscillation of the sling frame under which the shackles are suspended. The motion of actual floating crane under sea wave was measured to determine the mechanism of sling frame oscillation, and to verify from theoretical analysis the effectiveness of installing an active mass damper on the sling frame. For further ascertaining damper performance, a 1/40 size model of the crane barge mounted with the damper was tested in tank, which indicated reduction to 1/3 – 1/2 of sling frame oscillation, with good agreement between the theoretically estimated and measured results. Test at sea on actual floating crane equipped with active mass damper system confirmed that actuation of the system would reduce to roughly 1/2 the oscillation of sling frame.
Free-standing bridge towers, in general, suffer from vibrations caused by wind. In order to reduce vibrations, an actively-controlled mass damper was applied to Hakucho Bridge tower. In controlling vibrations, the node of the 2nd mode was selected as a settling point of sensors in order to maintain stability for higher order modes of vibration than that to be controlled. The damper was tested to verify damping performance by free vibration and measurement of vibrations caused by wind. High performance has been obtained from results of tests and the effectiveness of this method has been demonstrated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.